Tissue and airway impedance of excised normal, senile, and emphysematous lungs
Verbeken, Eric Cauberghs, M Mertens, I Lauweryns, Jm Vandewoestijne, Kp #
Amer physiological soc
Journal of applied physiology vol:72 issue:6 pages:2343-2353
We partitioned pulmonary resistance (RL) in excised normal, senile, and emphysematous human lungs at various distending pressures; peripheral resistance (Rp) was measured by means of retrograde catheters and lung tissue resistance (Rti) by means of pleural capsules. By subtracting Rp from RL and Rti from Rp, we obtained, respectively, central (Rcaw) and peripheral (Rpaw) airway resistance. We determined also lung volumes, the elastic recoil pressure-volume curve, and the forced expiratory volume in 1 s-to-vital capacity ratio (FEV1/VC). The functional data were related to morphometry: mean linear intercept (L(m)), diameter (dBAR), and density (n/cm2) of membranous bronchioles. In the three groups of lungs, Rti demonstrates a marked negative frequency dependence and increases with transpulmonary pressure. In emphysematous lungs, the increase of RL is mainly due to an increase of Rpaw; in addition, Rcaw and Rti are higher than normal. In the group of senile lungs, airway resistances are within normal range, but Rti is slightly increased. FEV1/VC is related to Rpaw and elastic recoil pressure; Rpaw is related to dBAR and n/cm2, and Rti is related to dynamic elastance and to L(m).